Lecture 14: Posterior Abdominal Wall

Question 1

What are the attachments of the Psoas major ms.; main action; innervation?

Answer 1

• TP’s and bodies of T12-L5
• Lesser Trochanter
• Main hip flexor
• Anterior rami of L1-L3

Question 2

What are the attachments of the iliacus m; innervated by?

Answer 2

• Iliac fossa, ala, anterior sacroiliac l to lesser trochanter
• Femoral nerve (L2-4)

Question 3

What are the attachments of the Quadratus Lumborum m.; innervation?

Answer 3

• 12th rib and TP - lliac crest and iliolumbar l.
• Anterior T12, L1-L4

Question 4

Where is a Psoas infection found (tissue wise)?

Answer 4

Deep to psoas fascia, between the fascia and muscle

Question 5

Signs and symptoms of a Psoas Abscess?

Answer 5

Back or flank pain, inguinal mass, fever, limp, anorexia, and weight loss

Question 6

What can elicit a positive psoas sign?

Answer 6

• Psoas abscess
• Retro-cecal appendix (appendicitis)
• Kidney and ureter pathologies
• Pathologies of the sigmoid colon

Question 7

What pathology is this?

Answer 7

Psoas Abscess

Question 8

What are the landmarks for the median, medial, and lateral arcuate ligaments; which have attachements to the diaphragm?

Answer 8

Median - superior to aorta

Medial - thickening of Psoas fascia (diaphragm attachment)

Lateral - thickening of fascia lining Quadratus lumborum (diaphragm attachment)

Question 9

What nerve is found just inferior to the lateral arcuate ligament?

Answer 9

Subcostal n. (T12)

Question 10

What are the 3 parts of the diaphragm and their attachment?

Answer 10

Sternal part: may NOT be present. Attaches to Xiphoid

Costal part: attahces to inferior 6 costal cartilages

Lumbar part: attaches to medial and lateral arcuate ligs.

Question 11

What are the spinal levels of the right and left crus of diaphragm?

Answer 11

Right: (larger and longer) - L3-L4

Left: L2-L3

Question 12

What comes thru Caval opening?

Answer 12

IVC and Rt. Phrenic n

Question 13

What comes through the Esophageal Hiatus?

Answer 13

Esophagus, ant. and post. Vagal trunks, and Esophageal branches

Question 14

What comes through the Aortic Hiatus?

Answer 14

Aorta, Thoracic duct, and sometimes Azygous/Hemi-azygos veins

Question 15

What spinal level is the body of the pancreas at?

Answer 15

L1

Question 16

What spinal level is the horizontal part of the duodenum at?

Answer 16

L3

Question 17

What is found anteriorly, superiorly and inferior to the Lf. Adrenal gland?

Answer 17

Superiorly: Lf. crus of diaphragm

Anteriorly: Stomach, spleen, and pancreas

Inferiorly: Left kidney

Question 18

How do the veins of the suprarenals differ?

Answer 18

Right: drains directly into IVC

Left: drains into L. Renal V.

Question 19

What is the innervation of the adrenal glands (plexus and nerve)?

Answer 19

• Preganglionic sympathetics from T10-L1
• Celiac plexus and abdominopelvic splanchnic nerves

Question 20

What is found anterior to the Rt. and Lf. Kidneys?

Answer 20

Right: liver, duodenum, ascending colon

Left: stomach, spleen, pancreas, jejunum, and descending colon

Question 21

Which spinal levels do the kidneys sit between?

Answer 21

T12-L3

*The left kidney is higher due to the liver

Question 22

What is the best point of incision for removing kidney; why?

Answer 22

• Posterolateral
• Will only require transection of transversalis fascia

Question 23

What are layers immediately external to renal capsule; where will a perinephric abscess form?

Answer 23

• Perinephric fat (abscess forms here)
• Renal Fascia

Question 24

What is the most anterior structure in the renal hilum?

Answer 24

• Renal vein (most anterior)
• Renal artery (middle)
• Renal pelvis (posterior)

Question 25

What structures are the ureters found posterior to in males and females?

Answer 25

Males: ductus deferns

Females: Uterine artery

Question 26

What are the 3 constriction points of the ureters?

Answer 26

1. Ureteropelvic junction
2. Crossing external iliac artery and/or pelvic brim
3. Ureters entering bladder wall

Question 27

What are the lymph nodes for foregut, midgut, and hindgut structures; where do they all drain into eventually?

Answer 27

Foregut: Celiac LN’s

Midgut: Superior Mesenteric LN’s

Hindgut: Inferior Mesenteric LN’s

*ALL drain into the Lumbar (lateral aortic) LN’s

Question 28

Which nerve is responsible for innervation of the posterolateral gluteal skin and skin in pubic region?

Answer 28

Iliohypogastric (L1)

Question 29

Which nerve is responsible for the skin in the upper medial thigh, skin over the root of penis, anterior scrotum, mons pubis, and labium majus?

Answer 29

Ilioinguinal (L1)

Question 30

Which nerve innervates the skin on anterior and lateral thigh to the knee?

Answer 30

Lateral femoral cutaneous (L2, L3)